Contact pin for electric plugs



G. MAAG-EICKENFELDER CONTACT PIN FOR LZLECTRIG PLUGS June 28, 1932.

Filed May 2-2, 1928 menaa James, 1932 PATENT. OFFICE IAAG-EGKENIELDEB, 0F ZURICH, SWITZERLAND comrac'r rm'ron. isnnormo noes I Application filed lay 28,1928, Serial H'o. 279,722, and in Germany June 27, 1887.

This invention relates to contact pins for electric plug and socket connections such as em loye ra '0 circuits.

5 Rigid contact ins are known having a wire spring formm a contact member and projecting from a ongitudinal slot in the pm. A disadvantage of such known contact 10. pins is that the contact surface between the wire s ring and the socket is usually very small t e result being that if the ressure applied to the contact surface is al owed to excoed a certain amount, in grams per square '15 millimeter, the contact surface wears away The contact member is so constructed that.

it has a large contact surface with the socket so that a good contact is obtained and there is less wear.

In the accompanying drawing are illustrated examples of construction in accordance with the present invention.

Fig. 1 shows a front elevation of a contact a pin with a contact member,

Fig. 2 shows a side elevation of the same a pin I y 3 is a longitudinal section of the same p 1 Fig. 4 is a longitudinal section of a plug pin with two contact members, v Fig. 5 is a cross sectional view of the form of the invention shown in. Fig. 3 and with the contact member in radially projected normal position,

in telephonic, heavy current and in grams per square millimeter remains with- Fig. 6 is a similar view of the same showing the contact member pressed inwardly.

a is the body of the pin b the contact membe%the stee springs which are of C shalpe.

en the pin 1s fitted into a suitable soc st to the contact member is pressed into the in body a diametricall to the axis of the p ug pin. The springs engage with their ends against two points of the contact bod b and cause the contact member to bear wit a con- 65.

tinual pressure a ainst the wall of the socket. The contact sur ace on the contact body is selected of such a size that aocordin to the total pressure of the springs f the loading in permissible limits. The contact surface also has a curvature of a radius correspondin with the radius of the bore of the socket.

11 order to obtain effective contact between the contact member and the pin body a the contact body is made conical on its inner side. In order to force the contact member 6 against the socket, the conical surfaces slide between the limbs of the spring 7 and form a so-called knife contact. The contact surfaces therefore automatically polish themselves clean.

I31 the case, for example, of two contact members, the operations are the same as in the case of plug pms with one contact member.

The engagement of the springs with the contact members 5 is effected su tantially at the middle thereof, in such a manner that the contact member always bears along itswhole length against the socket even in the case of conical sockets the contact member being capable of turning slightly on the spring f so that it can always hear effectively. a inst the contact surface of the sleeve even w on this is not truly cylindrical.

What I wish to secure by U. S. Letters Patent, is

1. An improved contact pin for electric lugs, comprising a body portion having. a

' intermediate its ongitudinal slot at a pomt 2 I Lac-mac ends, a contact member in said slot for movement radially of the body portion and also for longitudinal tilti movement and a O- I shaped spring in said body portion the ends 5 of which form a resilient support for said contact member.

y 2. An improved contact pin as claimed in claim 1, in which the contact member is provided with means for spreading the spring 13 limbs when said contact member is presse inwardly and thereby insure good contact.

3. An improved contact pin as claimed in claim 1, in which the contact member has a conical surface on its inner side to slide between the limbs of the sring and form a nice contact therewith w en said spring is pressed inwardly.

In testimony whereof I aflix my signature.

2) GOTTFRIED IAAG-ECKENFELDER. 

